An order of the class Reptilia (infraclass Archosauria) which is aquatic species including the alligators, caimans, crocodiles, and gavials. The group has a long fossil history from the Late Triassic, and its members are the closest living relatives of the extinct dinosaurs and the birds. The 23 living species are found in tropic areas of Africa, Asia, Austria, and the Americas. One form, the saltwater crocodile (Crocodylus porosus), has traversed oceanic barriers from the East Indies as far east as the Fiji Islands.